﻿// Parts Copyright 2008 Newgrove Consultants Limited
// Modified By John Diss 
// From original work:
//
// Copyright 2006 - Ricardo Stuven (rstuven@gmail.com)
//
// This file is part of MsSqlSpatial.
// MsSqlSpatial is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// MsSqlSpatial is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public License
// along with MsSqlSpatial; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

using System.Data.SqlTypes;
using GeoAPI.Geometries;
using Microsoft.SqlServer.Server;
using MsSqlSpatial;

public partial class UserDefinedFunctions
{
    /// <summary>
    /// Returns an element Geometry from a GeometryCollection,
    /// or <code>this</code>, if the geometry is not a collection.
    /// </summary>
    /// <param name="n">The index of the geometry element.</param>
    /// <returns>The n'th geometry contained in this geometry.</returns>
    [SqlFunction(IsDeterministic = true)]
    public static SqlBytes GeometryN(SqlBytes ewkb, SqlInt32 index)
    {
        IGeometry geometry = ConvertGeometry.ToGeometry(ewkb);
        if (geometry is IGeometryCollection)
        {
            try
            {
                return ConvertGeometry.ToSqlBytes((geometry as IGeometryCollection)[index.Value - 1]);
            }
            catch
            {
                return SqlBytes.Null;
            }
        }
        else
            return ewkb;
    }
} ;